.register{
    width: 400px;
    border: 1px solid #ccc;
    margin: 100px auto;
    padding: 10px;
    h2{
        text-align: center;
        line-height: 40px;
    }
    form{
        position: relative;
        padding-bottom: 30px;
        .submit{
            // 绝对定位脱离文档流不占据空间
            position: absolute;
            bottom: 0px;
            height: 30px;
            line-height: 30px;
            padding: 0px 20px; 
            left: 50%;
            transform: translateX(-50%);
        }
    }
   
}